Cutting means for book binding machine

ABSTRACT

Apparatus for use with a pair of thermoplastic strips of the type illustrated in U.S. Pat. No. 3,608,177 wherein one strip is formed with studs longitudinally spaced at intervals and a second strip apertured and counterbored at the same intervals is used to bind sheets apertured at the same intervals at locations spaced inward from one marginal edge is described. A pressure bar is first manually moved to operative position and a handle compresses the strips together by exerting a controlled force on the pressure bar. The handle then initiates movement of a support for a knife consisting of a length of metallic ribbon material having spaced horizontal stretches in horizontal alignment with excess stud lengths of the first strip projecting through the second strip, the ribbon being under tension to hold such stretches taut. As the support moves toward the studs a current is passed through the ribbon, heating it so that the ribbon functions to cut off the excess stud length slightly below the second strip. The current then is terminated as the support moves upward forming heads on the stud stubs filling the counterbores in the second strip. By this time, the ribbon has cooled and functions to cool and harden the heads. Retraction of the handle returns the support to initial position and releases the pressure bar. The handle also actuates a punch for the apertures in the sheets, the punch being located at a different station in the machine from the binding mechanisms.

This is a Division of Application Ser. No. 625,949, filed Oct. 28, 1975,now U.S. Pat. No. 3,994,055.

This application relates to an improvement in binding machines such asthose shown in U.S. Pat. Nos. 3,756,625 and 3,811,146. The improvementconsists in the provision of a relatively inexpensive, manually operablemachine to compress binding strips with a predetermined pressure withapertured paper between the strips, the studs on one strip fittingthrough holes in the sheets of paper and through the apertured secondplastic strip. The machine also has capability of being used as a punchto form the apertures in the sheets of paper. The thermo-plasticmaterial strips used in connection with this invention are adequatelydescribed in the aforementioned patents, as is the book which isproduced. The invention of the present application relates to a numberof improvements in the apparatus previously patented.

One improvement relates to the electrically heated cutoff mechanismwhich cuts off the excess lengths of the plastic studs of the firstplastic strip, then forms heads on the stubs of the cut off ends andcools and forms these heads to fill counter-bores in the second plasticstrip. The cut off device is a transversely extending piece of metallicribbon bent in a shape hereinafter described in detail and heated bypassing an electric current through opposite ends of the ribbon. Certainportions of the ribbon are tensioned and held horizontally betweensupports, and these horizontal portions are brought to bear against theplastic studs to cut and form the same. Preferably, the ribbon is asingle length of spring steel bent in straight stretches correspondingin number and position to the studs with angular stretches between thestraight stretches tensioned by spring clips. Preferably, the ribbon iscoated with a Teflon coating to overcome tendency of the thermo-plasticstud material to stick thereto. Passage of current between opposite endsof the ribbon heats the latter rapidly by resistance. After the currentis cut off, the ribbon cools rapidly. A mechanism is provided whereby asupport is moved horizontally rearwardly to cut the studs, the supportis then moved upwardly to form rivet heads of the stubs ofthermo-plastic stud material and meanwhile, the ribbon has cooled andthereafter functions as a heat sink to cool and harden the heads. Theelectrical circuitry for the ribbon knife indicates when a sufficienttime has elapsed to cool the heads and signals the operator to releasethe pressure from the plastic strips to remove the completed book.

A still further feature is the fact that the knife which cuts the studsis moved by springs and is thus not fixed in a path and speed ofmovement. Thus variations in hardness and melting point of thethermo-plastic stud material are accommodated by the "free floating"knife.

Another improvement over prior machines is that both cutting of thestuds and heading of the rivets is accomplished by the knife, which ispreferably heated while cutting and cooled while heading.

A still further feature is the use of a manually activated handle whichengages the pressure bar which compresses the sheets, and releases theknife support for cutting and heading. Further, the same handle punchessheets.

Another feature of the invention is a spring overload on the pressurebar assembly to prevent damage to the machine and produce constantpressure on the document being clamped regardless of thickness.

Another improvement relates to the pressure applying mechanism. It isimportant that a predetermined pressure be applied to the plastic stripsby means of a pressure bar which engages the top of the first strip andforces it toward the second strip. The operator of the apparatusmanually moves the pressure bar from a retracted position to anoperative position resting lightly upon the top of the first plasticstrip. Thereupon, the operator manually pulls a handle forwardly whichapplies additional downward force on the pressure bar until apre-selected pressure is applied, whereupon the pressure bar is latchedin position. At this point, blockage of movement of the knife supportingmechanism is released and the knife support is moved into cuttingposition by means of springs. Return of the operating handle to originalposition retracts the knife support.

Another feature of the invention is the fact that the same handle whichactuates the clamping and releases the knife support mechanism alsoactuates a punch which is located at a location removed from the bindingfunctions of the machine and is usable in forming holes in the sheet tobe bound. It will be understood, however, that other punching means orpre-punched paper may be utilized.

A further feature of the invention is the provision of interlock systemswhereby the knife support mechanism is not moved or heated when theoperating handle is moved unless the pressure bar has been manuallymoved from retracted to operative position. This permits punching ofpaper without heating the knife or moving the knife.

Another feature of the invention is the fact that there is no cut off ofthe excess stud material until the pressure bar applies to the bindingstrips a predetermined compressive force.

Another feature of the invention is the provision of a punch to punch aseries of holes spaced apart along a marginal edge of a stack of sheetsof paper or other material. In one form of the punch hereinafterillustrated and described, the male punch elements are circular pinshaving enlarged heads at their upper ends. The heads are received inapertures punched in a vertically reciprocating plate. The apertures areso constructed that on the down or punching stroke of the punch theheads of the male punch elements are depressed serially rather thansimultaneously and thus the force required to punch a given stack isreduced. On the upward or return stroke of the punch all of the pins areraised simultaneously. Other features of the punch reside in the facethat an oscillatory crank movement is transmitted to verticalreciprocation of the aforementioned plate with an economy of mechanicalcomponents.

Still another feature of a modified punch is that the punch elements aresquare or rectangular in cross-section to punch corresponding square orrectangular holes. These punch elements are projections from one or moreplates fastened to the vertically reciprocating plate heretoforedescribed. One of the features of this form of the invention is the factthat the punch plate and male punch elements can be stamped from a sheetof steel or other material, thereby reducing the number of parts andgreatly reducing the fabrication required to make the punch.

Other features of the invention reside in the simplicity of manufactureand assembly of the machine; and accordingly, its low cost as comparedwith previous machines to perform the same function.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawingsin which similar characters of reference represent corresponding partsin each of the several views.

In the drawings:

FIG. 1 is a front elevational view of a machine in accordance with thepresent invention.

FIG. 2 is a side elevational view thereof showing the handle inretracted position in full lines and in dot-and-dash lines in fullforward position.

FIG. 3 is a side elevational view with the side of the housing of themachine removed taken substantially along line 3--3 of FIG. 1 showingthe handle in retracted position.

FIG. 4 is a view similar to FIG. 3 with certain parts removed forsimplicity of illustration showing the handle in full forward positionand completion of performance of the punch function.

FIG. 4A is a fragmentary view of a portion of the mechanism behind thatshown in FIG. 4.

FIG. 5 is a view similar to FIG. 3 with certain additional parts removedto reveal underlying structure showing the structure prior tocommencement of the binding function.

FIG. 6 is a fragmentary view of a portion of the structure of FIG. 5showing the pressure bar manually placed in position for commencement ofthe binding function.

FIG. 7 is a view of a portion of the structure of FIG. 6 showingcompletion of the compression of the binding strips.

FIG. 8 is a sectional view taken substantially along the line 8--8 ofFIG. 1.

FIG. 9 is a partial plan view of the knife support mechanism of FIG. 8.

FIG. 10 is a sectional view taken substantially along the line 10--10 ofFIG. 9.

FIG. 11 is a fragmentary elevational view of a portion of the structureof FIG. 9 viewed from the right in FIG. 9.

FIG. 12 is a sectional view taken substantially along the line 12--12 ofFIG. 9 at the beginning of the binding cycle.

FIG. 12A is a fragmentary sectional view taken substantially along line12A--12A of FIG. 9.

FIG. 13 is a view similar to FIG. 12 showing the knife at the end of thecutting operation.

FIG. 14 is a view similar to FIG. 12 showing the knife at the end of theheading operation.

FIGS. 15-17 are views of the binding strip elements and associatedmachine structure at the positions in the cycle of operationcorresponding to FIGS. 12-14, respectively.

FIG. 18 is a fragmentary sectional view through the completed book alongline 18--18 of FIG. 17.

FIG. 19 is a schematic wiring diagram of the knife heating circuitry.

FIG. 20 is a front elevational view of the punch as viewed substantiallyalong the line 20--20 of FIG. 2, partially broken away to showadditional structure.

FIG. 21 is a fragmentary sectional view taken substantially along theline 21--21 of FIG. 20.

FIG. 22 is a fragmentary elevational view taken substantially along theline 22--22 of FIG. 21.

FIG. 23 is a fragmentary view similar to FIG. 22 of a modified punchconstruction.

FIG. 24 is an end elevational view of the structure of FIG. 23.

FIG. 25 is an enlarged fragmentary view of a portion of FIG. 23.

As shown in FIGS. 15-18 and as described in greater detail in the U.S.Pat. No. 3,756,625, the apparatus hereinafter described preferablyemploys for its use a first thermo-plastic strip 21 which is rectangularin cross section and has spaced at 1 inch or similar intervals along itslength depending from one side face thereof studs 22 formed with points23 at their lower ends. Strip 21 as well as second strip 24 ispreferably formed of a thermo-plastic material such as polyvinylchloride. Second strip 24 is also rectangular in cross section and is ofthe same length as strip 21, which is preferably the length of the bookto be bound. At intervals complementary to studs 22 are first apertures26 having counterbores 27 on their lower surfaces. The sheets 28 to bebound are formed with second apertures 29 adjacent one marginal edge,the spacing between apertures 29 being the same as that between thestuds 22 and first apertures 26. Operation of the apparatus, hereinafterdescribed, applies a downward pressure on the top of first strip 21, thestuds 22 of which have been inserted through the apertures 29 and theapertures 26 so that there are projecting portions 31 of studs 22, theextent of projection depending upon the thickness of the sheets 28. Theapparatus cuts the projecting portions 31 at a level slightly below thebottom of strip 24 leaving short stubs which are melted by a knife andmoved to form heads 32 filling the counterbores 27 of the second strip.After the thermo-plastic material forming the heads 32 has cooledsufficiently, the pressure against the first strip 21 is removed and acompleted book has been produced. The foregoing description of thestrips, sheets and method are similar to that of the operation and ofthe supplies used with the machines of U.S. Pat. Nos. 3,756,625 and3,811,146, and the book completed thereby.

The apparatus of the present invention has a casing 41, preferablymolded of a plastic material having a front 42 formed adjacent thebottom with a punching opening 43 into which papers are inserted forpunching of apertures therein. The casing 41 has a top 44 which alsofunctions as a platen, as hereinafter explained. There is a punch edgeguide 46 adjacent to the punch opening 43 and a binding edge guide 47 onthe top 44 which are adjustably positioned to be engaged by one sideedge of the sheets to be punched or bound respectively. An invertedU-shaped handle 48 has spindles 49 which extend through the sides ofcasing 41 adjacent the rear thereof. The handle is pulled manually fromthe solid line retracted position of FIG. 2 to the dot-and-dash lineforward position which indicates the end of either the punching or thebinding position of the handle 48. A drawer 51 for scrap paper punchedfrom the sheets by the punching function or severed ends of the plasticstuds cut during the binding portion is provided. Said drawer 51 is slidforwardly for dumping of the debris when it has accummulated.

Extending along either side of the machine inside the sides of casing 41are vertical side plates 52 suitably spaced apart and rigidly attachedby mounting means 55. Extending between the side plates 52 arehorizontal punch platen 53 on the lower and forward end of the machineand binding platen 54 on the top and rear of the machine. Binding platen54 is formed with a transversely extending shallow recess 56 to receivesecond strip 24 and there is an opening 57 below recess 56 through whichproject the portions 31 of studs 22 below strip 24. As best shown inFIG. 8, there is a transverse substantially vertical rear edge stop 58for the rear edge of the sheets supported on platen 54 which squaressaid edges with the rear edge of strip 24 when the latter is in recess56. Stop 58 is flexibly supported by support 59. Certain of the strips21, 24 may be wider than the others for certain types of bindingfunctions, and to accommodate such strips the stop 58 may move rearwardwhen the wider strips are inserted in the recess 56. Support 59 isattached to side posts 64 which extend up above the level of top 44adjacent the rear of each side of the machine. Extending between theposts 64 is a transverse pressure bar 61 which applies downward pressureto first strip 21. At each end of pressure bar 61 are pins 62, the upperpin 62 fitting into a horizontal slot in the inward facing surfaces ofpost 64 and then being movable into an elongated vertical slot 66 in theinward faces of side posts 64. When the upper pin 62 is in horizontalslot 63 and pushed rearwardly thereof, the pressure bar 61 is retractedfrom its operative position and is tilted upwardly-rearwardly out of theway of the insertion of the sheets 28 and first strip 21. When the bar61 is moved manually forwardly and downwardly, the pins 62 slide invertical slots 66. Upper pin 62 is pivotally connected to link 67 whichextends below top 44 and lies immediately outside plate 52. The lowerend of link 67 is pivotally connected by means of pin 70 to crank arm68, the opposite end of which turns the non-circular portion oftransverse horizontal shaft 69. Also turning with shaft 69 is a piececarrying a ratchet segment 71. Plate 52 is formed with an arcuate slot72 concentric with shaft 69 and pin 73 in crank arm 68 oscillates inslot 72.

Directing attention now to FIG. 3, in a position outside of the path ofmovement of crank arm 68 is a shaft extension 76 and surrounding thesame and oscillatable relative thereto is a bushing 77 which receivesconnecting pins 78 attached to the handle 48 so that the bushing 77oscillates about the center of shaft extension 76 as the handle 48 ismoved from its retracted to full forward position. Turning with bushing77 is an irregularly shaped crank 79 which is pivotally connected at itsleft rear as viewed in FIG. 3 by means of pivot 82 to a longitudinallyforwardly extending link 81. Adjacent the forward end of the machine isa punch crank 83 which is pivotted to plate 52 by punch pivot 84. Thepunch mechanism is hereinafter described; the purpose of the mention ofcrank 83 and pivot 84 at this point is merely to show positive locationof the forward end of link 81 which is connected to crank 83 by pivot86. Intermediate pivots 82 and 86 is an upward exxtension 87 of link 81formed with an angularly shaped slot 88 as best shown in FIGS. 3 and 4.Directing attention now to FIG. 5, fitting within slot 88 is pin 92relative to which pivots pawl 91 shaped to engage the ratchet segment71. Pin 92 pivotally connects pawl 91 to a link 93, the forward-downwardend of which carries a pin 94 connected to fitting 98 bearing againstthe upper end of compression spring 96 which is held in an aperture 99in plate 52 by support 97. When the handle 48 is pivoted from retractedposition to forward position, if the pressure bar 61 has been movedforwardly and downwardly so that the ratchet segment 71 is partiallyturned from the position of FIG. 5 to the position of FIG. 6, as thehandle 48 moves the link 81 is moved rearwardly and downwardly from theposition of FIG. 3 to the position of FIG. 4 and the pin 92 slides fromits up position in slot 88 of FIG. 3 to its down position of FIG. 4causing the pawl 91 to move from the position of FIG. 5 to the positionof FIG. 7 which turns the ratchet segment 71 in a clockwise direction asviewed in FIG. 7 until the spring 96 compresses under a predeterminedapplication of force whereupon movement of the pawl 91 terminates. Asthe ratchet segment 71 is turned clockwise by the pawl 91, a crank 68exerts a downward pressure on link 67 and thus on pressure bar 61 sothat a predetermined compressive force is applied by the pressure bar 61on the first strip 21. By reason of the shape of slot 88, when pin 92enters the middle of slot 88 link 93 moves clockwise and pawl 91 becomespractically aligned therewith. Therefore the upward pressure exerted onpressure bar 61 by reason of the compression of papers 28 below bar 61does not return the parts to initial position. As best shown in FIGS. 4and 7, when the pawl 91 is exerting turning force on segment 71 pins 92,94 and pawl 91 are almost in a straight line. Pin 92 bears against thetop edge of the middle of slot 88 and segment 71 is locked in place.Slot 88 is long enough to permit full forward movement of handle 48.

Spring 96 functions as an overload mechanism, retaining fitting 98 andpivot pin 94 in a fixed position until such time as the resistance ofcompressed strips 21 and 24 with interposed paper 28 forces spring 96 tobegin to compress, allowing fitting 98 and pin 94 to move withinaperture 99 in plate 52, preventing over-compression of the bound bookor damage to the machine. It also functions to ensure a predeterminedpressure being applied to the book while it is being made. Spring 96also accommodates variations in operator technique of inserting stripsand lowering the pressure bar 61. Still further, the spring 96accommodates different kinds of paper which may be used and particularlythe effect of air between the sheets, which varies with different typesof paper. When the binding operation is completed, handle 48 is returnedto rearward position and this returns the link 81 to its forwardposition shown in FIG. 3. The pressure bar 61 may be raised manuallybecause return of link 81 to forward position disengages the pawl 91from the ratchet segmentt 71.

As shown in FIGS. 3 and 8-10, there is a lobe 101 on crank 79 which fitsinto an enlarged opening 102 in plate 52.

Mounted for horizontal reciprocation between side plate 52 and below thelevel of platen 54 is horizontal transverse knife support 106, the endsof which are connected to drive plates 107 which reciprocate immediatelywithin plates 52. Horizontally elongated slot 108 is formed in plate 107for passage of shaft 69 so that plate 107 and support 106 mayreciprocate above the level of shaft 69. Further, horizontally elongatedslot 110 is formed in plate 107 to receive enlarged head rivet 114 (seeFIG. 8) fixed to plate 52 so as to retain plate 107 in close slidingcontact with plate 52. Plate 107 is also formed with a slot having asurface 109 which is non-circular relative to shaft 69. The lobe 101projecting through plate 52 fits into the opening in plate 107 and atthe upper end of its movement (when the handle 48 is in retractedposition), bears against surface 109 to prevent movement of plate 107when handle 48 is up. Lobe 101 also functions when handle 48 is returnedto retracted position to return plate 107 to initial position by movingplate 107 and support 106 to the left as viewed in FIG. 8. When thehandle 48 is in forward position, the lobe 101 moves downwardly out ofcontact with the surface 109. (See dotted line position in FIG. 10).Horizontal tension springs 111 are fastened at their rear to a rearstationary anchor 112 interconnecting opposite plates 52 and at theirforward ends are fastened to an ear 113 attached to plate 107. Hence theplates 107 are biased rearwardly by spring 111 from the knife retractedposition shown in FIG. 8 to cutting position and this movement ispermitted when the lobe 101 is in down position. When the handle isreturned from forward position to retracted position, the lobe 101engages the surface 109 as the handle approaches retracted position andmoves the plate 107 and hence the knife support 106 to the left asviewed in FIG. 8.

Plate 107 at its right-hand end immediately above slot 108 is formedwith a shoulder 103. When pin 73 is elevated (i.e., in the positionshown in FIGS. 10 and 12), it engages shoulder 103 and prevents movementof plate 107 to the right. Hence, when the pressure bar 61 is elevatedand pushed rearwardly (i.e., when there is no binding function to beperformed), the pin 73 prevents movement of plate 107 despite theoscillation of crank 79 and the fact that lobe 101 is not in engagementwith cam surface 109. As shown in FIG. 13, with the pin 73 out ofengagement with shoulder 103 there is no obstable to movement of thesupport 106 to the right so that the knife 122 may perform its cuttingfunction.

Above knife support 106 is a removable knife support 116 which can bereplaced when the knife hereinafter described has been damaged. Theremovable support 116 is connected to the support 106 by spring clips117 which hold the two parts together as viewed in FIG. 12. By pullingthe clips 117 in a counterclockwise direction, the upper right end ofspring 117 is brought out of engagement with the horizontal portion 118of support 116, permitting removal of support 116 and the partsassembled thereto.

Removable support 116, as best shown in FIGS. 9 and 11, at its rearwardend has spaced vertical ribbon supports 121 which support knife 122. Ashas been mentioned, knife 122 is a continuous ribbon of spring steelpreferably plated with a non-corrosive metal such as nickel then coatedwith Teflon so that the plastic stud 31 material does not cling thereto.A horizontal stretch 123 of ribbon 122 is tightly stretched between eachpair of supports 121 and the spacing of horizontal stretches 123coincides with the position of the stud material 31. Between horizontalstretches 123 and thus between the pairs of supports 121 the ribbon 122slants downwardly in angular stretches 124 meeting at a point where theyare engaged by hold-down springs 126 which are irregularly shapedmembers as best shown in FIG. 12 and slide in grooves 127 on theunderside of portion 118 of removable support 116. Thus the springs 126tension the ribbon 122 and cause the horizontal portions 123 to bestretched taut between the supports 121 so as to perform the cutting andheading function. The ends of ribbon 122 are bent around end posts 128at opposite ends of support 116.

Drive plate 107 is provided with a pair of upwardly-rearwardly slantedslots 141. The opposite ends of support 106 are provided with a pair ofpins 142 which fit into slots 141. When the support 106 has moved to thefull right position (contrast FIGS. 12 with FIG. 13), it engages astationary abutment 143 fixed to the frame of the machine. It will benoted that the underside of platen 54 is formed with an undercut 144,immediately to the left of recess 56. As springs 111 pull the support106 to the right, when the support 106 engages abutment 143, furtherspring tension causes the pins 142 to move upwardly in the slots 141until the position of FIG. 14 is attained. A spring 146 depending fromsupport 106 and resiliently engaging the top of shaft 69 biases support106 upwardly to the position of FIG. 14.

Integral with and depending from housing 54 and in horizontal alignmentwith the straight stretches 123 of knife 122 are vertical ribs 147 thelower ends of which are supported by supports 148 which are joined toabutment 143. The first time the knife is actuated, the hot horizontalstretches 123 cut horizontal slots 149 in ribs 147, the vertical heightof said slots being about equal to the thickness of material ofstretches 123. Thereafter, each time the hot knife is actuated it movesrearwardly through the slots 149 and when it retracts the margins ofslots 149 wipe from the stretches 123 any plastic material which hasadhered thereto when the studs 31 were cut.

As shown in FIG. 19, the electrical system for control of the heatingand cooling of the ribbon 122 is relatively simple. A transformer 131 isprovided inside the casing 41. The secondary coil of the transformer 131is connected to the opposite ends of the ribbon 122 which is heated byresistance when current passes through transformer 131. The circuitrywhich controls energization of the primary coil of transformer 131 isrelatively simple as is shown in FIG. 19. When pressure bar 61 is movedfrom the position of FIG. 5 to FIG. 6, switch 132 is closed. Whensupport 106 moves rearwardly from the position of FIG. 12 toward FIG.13, switch 133 is closed and this energizes the coil of relay 134 andheats knife 122. Relay 134 has a pair of contacts which are held closedfor an approximately seven second delay. Signal light 138 is energizedduring the timed second delay; and when the relay contacts open afterthe timed delay, the lamp 138 is de-energized notifying the operatorthat it is proper to replace the handle 48 from forward position toretracted position. Meanwhile, when support 106 has reached the positionof FIG. 13, switch 137 is opened, de-energizing the primary coil oftransformer 131 and allowing knife 122 to begin to cool. At the end ofthe timed delay, knife 122 has cooled sufficiently to cool the heads 32as shown in FIG. 14.

BINDING OPERATION

The binding function of the apparatus is as follows:

The operator, with the handle 48 in upward-rearward position shown inFIG. 3, manually inserts the strip 24 in recess 56. A plurality ofsheets 28, suitably formed with holes 29, is placed over the strip 24,one edge of the sheets being in contact with stop 47 and another withstop 58. Thereupon, the studs 22 of strip 21 are inserted through theholes 29 in sheets 28 and through the holes 26 in strip 24. The positionof the parts is then substantially as in FIG. 15. Thereupon, theoperator pulls pressure bar 61 forwardly and downwardly from theposition of FIG. 5 to the position of FIG. 6 so that the pressure barrests upon the top of strip 21 and partially compresses the sheets 28.This closes switch 132 and segment 71 moves to the position of FIG. 6.

Thereupon, the handle 48 is pulled forwardly, causing the link 81 tomove rearwardly from the position of FIG. 3 to the position of FIG. 4.The sliding motion of pin 92 in the initial upward-rearwardly slantedportion of slot 88 causes the pawl 91 to engage one of the teeth ofratchet segment 71. Further movement of the handle 48 causes the pawl 91to push ratchet segment 71 in a further clockwise rotation to move fromthe dot-and-dash position of FIG. 6 to the position of FIG. 7 until thespring 96 compresses as a result of a predetermined pressure of thepressure bar 61 on the stack of sheets 28. The movement of segment 71 ina clockwise direction, as viewed in FIG. 7, causes the crank arm 68 tomove in a clockwise direction, pulling the link 67 and the pressure bar61 downwardly, applying a force on the plastic strips 21 and the sheets28 underneath the same. Oscillation of arm 68 oscillates shaft 69, andthus the downward force on each end of pressure bar 61 is equalized. Ascrank arm 68 moves to the position of FIG. 7, pin 73 moves out ofcontact with shoulder 103. Simultaneously, lobe 101 moves out of thecontact with the cam surface 109. Thereupon, springs 111 pull the driveplate 107 to the rear right (as viewed in FIGS. 7 and 9-12). As soon asthe plate 107 begins to move to the right, switch 133 is closed. Sincethe switch 137 is normally closed, the transformer 131 is energized,heating the ribbon 122. The relay 134 is closed for approximately sevenseconds and lamp 138 is illuminated for such period.

As ribbon 122 moves from the position of FIG. 12 to the position of FIG.13, the straight ribbon sections 123 cut off the excess stud material31, leaving stubs of stud material 22 below the level of second strip24. When the support 116 engages abutment 143, switch 137 is opened,causing ribbon 122 to begin to cool. Continued force of springs 111causes the pins 142 to rise in the slots 141 and the ribbon 122 moves tothe position of FIG. 14, filling counterbore 27 in second strip 24 withplastic material. During the timed delay of relay 134, the cool ribbondraws heat out of the stub material forming a solid head 32 filling thecounterbore 27 and hardening the same.

When the light 138 is extinguished after the timed delay, the operatormoves the handle 48 to rearward position. This causes the link 81 tomove from the position of FIG. 4 to the position of FIG. 3 so that thepin 92 rises to the upper end of slot 88. This causes segment 71 toreturn to the position of FIG. 6. Lobe 101 contacts surface 109,returning support 106 to the initial position of FIG. 12. As the knife122 retracts, the margins of slots 149 wipe off any accumulation ofplastic on the sections 123 of knife 122. Thereupon, the operator liftsbar 61 and moves it rearwardly to the position of FIG. 5. The completedbook is then removed from the machine. As shown in FIG. 18, heads 32fill counterbores 27, binding sheets 28 tightly between strips 21, 24with studs 22 through the holes 29 in sheets 28.

PUNCH MECHANISM

In a preceding portion of this Specification it has been explained thatforward movement of handle 48 from the dotted line position of FIG. 3 tothe position of FIG. 4 causes oscillation of the punch crank 83 from theposition of FIG. 3 to the position of FIG. 4. Immediately below thelevel of punch opening 43 in the front 42 of casing 41 and spacedrearwardly at a point behind edge guide 46 is a female die plate 151extending horizontally transversely of the machine, the upward turnedouter ends of plate 151 being secured to side plates 52 by pivot bolts84, as best shown in FIG. 20. Holes 152 are formed in plate 151, thenumber and location thereof depending upon the holes to be punched inthe paper. The rearward edge of plate 151 is bent vertically upwardly ina stretch 160 which serves as a stop, limiting inward insertion ofsheets 28. The distance between stop 160 and holes 152 determined thedistance from the marginal edge of the sheets 28 at which the holes 29are punched.

Immediately above plate 151 is a horizontal transverse guide plate 153and there is a gap 155 between plates 151 and 153 which limits thequantity of paper which may be punched at one time. Plate 153 is formedwith holes 154 which are vertically aligned with holes 152.

Vertically reciprocating punch plate 156 is in vertical alignment withholes 152 and 154 and is spaced forwardly from the upturned rear edgesof plates 151 and 154 and spaced forwardly therefrom by spacer 157.Immediately in front of plate 156 is a front plate 158. Pins 159 passthrough holes in the upturned edges of plates 151, 154 and through frontplate 158 and also through spacer 157. The pins 159 pass throughvertically elongated slots 161 in plate 156 so that the plate 156 mayreciprocate relative to the stationary elements of the apparatus. AnL-shaped secondary guide 162 is fixed to the front face of thevertically upturned portion of plate 153 and is also apertured inalignment with apertures 152, 154.

Male punches 163 which are in the form of round cross section pins arein vertical alignment with holes 152, 154. The lower ends of pins 163are ground concave so as to cooperate with holes 152 to punch paper inthe gap 155. The upper end of each pin 163 is formed with an enlargedhead 164 which is received in a slot 166 in punch plate 156. As bestshown in FIG. 22, at the left or center of the plate 156 the upwardextent of slot 166 is slightly more than the thickness of head 164 butprogressing either direction from the center the upward extension ofslots 166 increases to a maximum on each end. Below slots 166 are inwardextending shoulders 169 formed integral in plate 156, which engage underthe heads 164. Thus as the plate 156 is depressed, each head 164 of pins163 serially proceeding from the center of the machine outward towardeither side is depressed by the top of slot 166 engaging the top of head164. In other words, all of the pins 163 are not depressed at once butthey are depressed sequentially in pairs matched relative to thecenterline of the machine. Hence the force required to punch the entireseries of holes in the paper is reduced because all of the holes are notpunched simultaneously.

Actuation of vertical reciprocation of punch plate 156 is accomplishedby oscillation of punch crank 83. It will be noted that plate 156 hasoutward extensions 167 at either end which project through slots inplate 52 and have upward extended ears 168. On the inward side of crank83 is an eccentric boss 171 and said boss 171 fits in a hole in thelower end of vertical lever 172. Lever 172 at its upper end is formedwith a truncated segmental slot 173 as best shown in FIG. 3 throughwhich the extension 167 protrudes.

OPERATION OF PUNCH

As the handle is moved from rearward position of FIG. 3 to the forwardposition of FIG. 4, crank 83 oscillates clockwise as viewed in FIGS. 3and 4 and this causes eccentric boss 171 to pull plate 156 downwardbecause extension 167 is depressed vertically by the downward movementof lever 72 with slot 173 against which extension 167 bears. Turningattention now to FIGS. 20-22, when the plate 156 is depressed, by reasonof the top edge of each slot 166 contacting the top of head 164, thepunches 163 are depressed sequentially proceeding from center to eachend of plate 156. The depression of pins 163 causes the bottom end ofthe pin 163 to punch a hole in paper in gap 155 by reason of shearingaction relative to holes 152. The holes in guide plate 153 and secondaryguide 162 keep the pins 163 in vertical alignment with the holes 152 and154. When the handle is returned to rearward position, the shoulders 169pull the heads 164 of each of the pins 163 upwardly simultaneouslypermitting removal of the paper.

MODIFIED PUNCH

In FIGS. 23 and 24 is shown a modification of the punch heretoforedescribed in which square or rectangular holes are formed in the paperrather than the round holes of the preceding modification. A punch body176 which consists of an integral piece of metal is bolted to punchplate 156a by means of bolts 177. Depending from plate 176 is a seriesof male punch projections 178 which are rectangular or square in crosssection and are ground at their lower ends in a manner similar to thegrinding of pins 163 so that the male punch elements 178 will cooperatewith the holes 152 (which are square or rectangular rather than round inthe modified form of the punch) to punch square or rectangular holes inthe paper.

The structure of FIGS. 23 and 24 resembles that of precedingmodification and is incorporated in similar reciprocating structure.Corresponding elements are designated with the same reference numeralsas in the preceding modification followed by subscript a.

A unique feature of the structure of the punch of FIGS. 23 and 24 isthat the body 176 and integral projections 178 are a unitary piece ofmetal and can be stamped from a piece of sheet steel or other materialin a single stamping operation, thereby eliminating the necessity ofindividual pins 163 as in the preceding modification and in conventionalpunches. As shown in FIG. 23, the lower ends of the projections 178 arenot uniform but are of varying lengths so that the holes are punched inthe paper sequentially rather than simultaneously proceeding from thecenter of the machine outwardly.

As best shown in FIG. 25, a preferred shape of distal end of projection178 is shown. The bottom edge at each end curves upwardly-inwardly instretches 179 and at the middle is a semi-circular edge 181. The radiusof curvature of stretch 181 is substantially less than that of stretches179. Particularly when punching extremely large thicknesses of paper,the curved portion 181 curls up the rectangular cutouts of the paper sothat they are more easily driven through the holes 29 on the downstrokeof the punch.

We claim:
 1. Cutting means for use with a plurality of thermoplasticmembers comprising locating means for said members, a knife formed of athin narrow ribbon of metal, electrical means for heating said knife byresistance, a support for said knife, a frame, guide means on said framefor guiding movement of said support from a first position remote fromsaid members to a second position at which said knife cuts through saidmembers, and support actuating means to move said support from firstposition to a second position and back to first position, saidelectrical means having a first switch to pass current through saidknife as said support leaves first position and a second switch to cutoff current to said knife when said support has heated said knifesufficiently to cut said members as said support reaches secondposition, said guide means having a third position in a directionrelative to said second position at a right angle to the direction ofmovement of said support from first to second position whereby saidknife first forms heads on stubs of cut material of said members andthen cools said heads.
 2. Cutting means for use with a plurality ofthermoplastic members comprising locating means for said members, aknife formed of a thin narrow ribbon of metal, electrical means forheating said knife by resistance, a support for said knife, a frame,guide means on said frame for guiding movement of said support from afirst position remote from said members to a second position at whichsaid knife cuts through said members, support actuating means to movesaid support from first position to a second position and back to firstposition, said ribbon being bent in straight stretches and angularstretches intermediate said straight stretches and said support havingprojections across which said straight stretches lie, and resilientmeans on said support bearing against said ribbon at said angularstretches to draw said straight stretches taut.
 3. Cutting meansaccording to claim 2 which further comprises a plurality ofsubstantially vertical ribs fixed relative to said locating meanspositioned in the path of movement of said straight stretches and eachformed with a horizontal slot whereby as said knife moves between firstand second positions said straight stretches pass through saidhorizontal slots and on the return of said knife to first positionplastic material is wiped off said straight stretches by the margins ofsaid slots.
 4. Cutting means for use with a plurality of thermoplasticmembers comprising locating means for said members, a knife formed of athin narrow ribbon of metal, electrical means for heating said knife byresistance, a support for said knife, a frame, guide means on said framefor guiding movement of said support from a first position remote fromsaid members to a second position at which said knife cuts through saidmembers. support actuating means to move said support from firstposition to a second position and back to first position, compressionmeans applying a force tending to move said members in a direction alongtheir axes, and an interlock between said compression means and saidsupport means restraining movement of said support means from firstposition except when said compression means is actuated.
 5. Cuttingmeans according to claim 4 in which said electrical means comprises athird switch, said third switch being closed only when said compressionmeans is actuated, said third switch when open cutting off current tosaid knife so that said knife is heated only when said compression meansis actuated.
 6. Cutting means according to claim 4 in which saidactuating means comprises a spring to pull said support from first tosecond position and a handle to return said support to first positionand to stress said spring.